Date of Award

Spring 1999

Document Type

Restricted Thesis

Terms of Use

© 1999 Anna D. Tischler. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts

Department

Biology Department

First Advisor

Tami Mysliwiec

Second Advisor

Amy Cheng Vollmer

Abstract

SP10 is a spore-converting bacteriophage that infects Bacillus subtilis and rescues the sporulation negative phenotype of spo0J mutants. The mechanism used by SP10 to suppress spo0J mutations was studied by attempting to detect viral homologs to B. subtilis sporulation genes. A viral homolog to spo0J might complement the spo0J mutation; homologs to spo0A, sigH, or sigE might activate the transcription of genes downstream from spo0J in the sporulation pathway, bypassing the need for a functional Spo0J protein. PCR reactions were performed on SP10 DNA using degenerate primers targeted to highly conserved regions of each gene and the resulting fragments were sequenced. While none of the PCR products showed significant homology to sporulation genes, a viral ribonucleotide reductase (nrdE) homolog was detected. Two other PCR products encoded open reading frames with limited homology to known proteins. Because the phenotype of SP10-infected B. subtilis is similar to the phenotype of degU(Hy) mutants, the expression of degU was analyzed using a lacZ fusion. Infection with SP10 caused increased degU::lacZ activity during stationary phase. Mutational analysis revealed that a functional DegU protein is required for suppression of the spo0J mutation by SP10 infection but not for SP10-induced catabolite-resistant sporulation in wild-type cells. Analysis of sporulation by spo0J and soj mutants suggested that SP10-induced catabolite-resistant sporulation may depend on the ratio of the spo0J and soj gene products. Finally, a partial restriction map of the SP10 genome was created including the restriction enzymes EcoRI, EcoRV, and SmaI.

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